Formation of N-oxido copper ethylenediaminetetraacetate and propanediaminetetraacetate and their selective degradation to iminodiacetate and propanediaminediacetate

Abstract

N-Oxido copper(II) ethylenediaminetetraacetate Na_4n[Cu₂(edtaO₂)₂(H₂O)₄]_n·13nH₂O (2) (H₄edta = ethylenediaminetetraacetic acid, C₁₀H₁₆O₈N₂) and N-oxido copper(II) 1,3-propanediaminetetraacetate Na_5nO_n[Cu₂(HpdtaO₂)₂Cl]_n·12.5nH₂O (4) (H₄pdta = 1,3-propanediaminetetraacetic acid, C₁₁H₁₈O₈N₂) were obtained from the reactions of copper(II) edta and pdta respectively with hydrogen peroxide. The copper ions in 2 and 4 are hexa-coordinated by edtaO₂ or pdtaO₂ ligands, forming 1D chain structures. Further reactions of 2 and 4 at lower pH values result in the isolation of copper(II) iminodiacetate K[Cu(ida)(H₂O)₂Cl] (3) (H₂ida = iminodiacetate acid, C₄H₇O₄N) and copper(II) propanediaminediacetate [Cu₂(pdda)₂]_n·nH₂O (5) (H₂pdda = propanediaminediacetic acid, C₇H₁₀O₄N₂), respectively, which show the selective degradation of ethylenediaminetetraacetate and propanediaminetetraacetate.